Insulator



A. 0.*AusTlN. INSULATOR. APPLICATION FILED AUG.I2, 1918.

1,360,352, Pawnted1N0v.3o,192.

. I Cf/MM/ i fgu@ f@ @www g je ,U'Nrranv STATES PirENT OFFICE. Y

ARTHUR O. AUSTIN, OF BARBERTON, OHIO,MA`SSIGNOR, BY MESNE ASSIGNMENTS, T0 THE OHIO BRASS COMPANY, OF MANSFIELD, OHIO, A CORPORATION OF NEW JERSEY.

INSULATOR.

Specification of Letters Patent. Patented NOV. 30, 1920.

Original application tiled May 29, 1916, Serial No. 100,481. Divided and this application led August 12,

1918, Serial No; 249,416. v

To ZZ fw /wm it may concern y Be it known that I, ARTHUR O. AUSTIN, a citizen ofthe United States, residing at Barberton, in the` county of .Summit and State of Ohio, have invented certain new and useful Improvements in Insulators, of

y which the following is a specification.

This invention relates to insulators in which `one or more of the parts have connected surfaces roughened or sanded to provide means for cementing the parts together, and at the same time to permit greater resilience between them.

The invention consists in the novel construct1on, comb1nat1on and arrangement of the several parts;

` In the drawings- Figure/1 is a View partly in section of an insulator constructed in accordance with the principles of this invention.

Fig. 2 is an enlarged detail of a portion of the construction shown by Fig. 1.

Fig. v3 is a detail showing'the edge of the metallic shell coated with yielding material.

Fig. 4 shows the adjacent portion of the insulating member so coated; and

Figs. 5 and 6 are' detail views showing projecting particles attached to the insulating member.

This application is a division of my prior application, Serial No. 100,481,filed May 29,

1916, and patented November 19, 1918, No.

1,284,975. vThe present invention relates. more particularly to an insulator made up ofa number of parts, one or more of which are not insulating material, but are preferably of metal so that this application is limited to an insulator in which the insulating member formed with a sanded attaching surface is connected by cement to one or more metal parts. i

In insulators which consist of a number ofv parts, either of similar or ldifferent materials, it isy customary to unitethe several parts by .means of cement.- The surfaces which are' so connected may be knurled or roughened for affording anchoring surface for the cement, and thereby 'connectingl the parts more rigidly together, but if the parts are too rigidlyjoined they may be subjected to undue' stresses and strains caused by changes in temperature and other conditions which impair, rather than improve the insulators. The unglazed surfaces either provvided with grooves, or made plain, may give fairly satisfactory results, but there are certain'conditions which it is desirable to o tain in insulators,l which can be better obtained if the surfaces are coated with glaze, not' only` where they are exposed to the weather, but also where they are in contact the porcelain insulator, namely, increased electrical resistance, but it would produce a mechanically weak joint which would soon break apart or loosen up on account of the cement not` adhering to the surface.

To overcome this mechanical and physical weakness, Vand to secure the properties which are desired inan insulator, it is found practicable to-coat the surfaces of the insulating material to be connected before the insulating member is fired in the kiln with material which will produce a glazed Surface, and while this coating is still wet, to sprinkle sand or crushed material which has,`or has not been vitrified, but which will adhere to this coating on account of it being in a moist and sticky condition when the particles are first applied. Crushed unvitrified clay or sand is preferable, yfor the reason that if the material applied to the body of the insulating member has about the same coefficient of expansion and contraction in firing as the insulating member itself, there will-be less tendency for the particles to chip or break after removal from the kiln.

When insulating members are. thus preparedf and are then placed in the kilnand l lvitrified, it is found that the insulating mem-y ber itself is practically covered with glaze,y

thus giving a surface which adds to the electrical resistance, and vprevents the absorption of moisture, but leaves the points of the applied material, or tparticles thereof projecting above the glaze andl these points 'may be practically free of glaze at the\ outer ends, or entirely covered, the bases and sides of the particles being held firmly in the glaze and forming ay substantial continuation of the insulating member itself.

which are so formed, the roughened surfaces Before assembling the insulator parts v are coated with an elastic or yielding material, which may be spread upon the surface in any convenient manner, as for example, by dipping the portion of the insulator to be coatedinto the material in liquid or semiliquid form so that the material is distributed over the surface and due to capillary attraction is drawn entirely or partially away 'from the points or tips of the roughened particles and accumulates at the bases of the projections. This leaves the ends of the projections free to extend into the connecting cement, free or partially so of the coating material, .so that they will engage the cement or binding material between the parts. Since these projections 'are of considerably smaller area than the surface of the main body to which they are attached, a force or strain transmitted between the insulator parts so connected, or between a part and the connecting cement will be concentrated in the projections. The projections being of elastic material and having a smaller section than the main body of the insulator, the stress or strain between the connected parts which tends to disrupt them will be in inverse proportion to the crosssectional area of the projections and will be directly proportional to their length. It is evident then that if the projections are of sulicient length and of small enough ,cross-v section, the internal strain or yielding stress between the connected parts can be almost entirely taken up by the projections, thereby keeping down the stress in the main insulating members themselves.

When metal parts are assembled and attached to an insulating member, the connecting surfaces may be prepared and treated .the saine way, but it is usually sufficient tov simply roughen or groove the surface of the metal part so that a connecting cement will adhere firmly thereto, the yielding connection being provided at the sanded surface of the insulating member, as above described.

When this invention is applied to an insulator in which one of the insulating members is interposed between metal parts, or is connected to a metal part, the connecting surfaces of the insulating member is prepared Yas above described. For example, the

connecting surface of an insulating member 1 may be coated with a rather thick layer of glaze 2, as shown vin Fig. 5, in which particles '3 are placed before 'vitrifying, the glazeextending quite a distance or partially upon the sides of the particles, causing the particles to be quite rigidly held when the member so prepared, is vitrified. A coating of elastic or yielding material 4, such as wax or parafiin is then applied, the hollows between the points of the projections fillingvup by capillary attraction, leaving the tips of the projections of the` particles yielding material.

If desired, this prepared surface can be extended entirely over the surfaces in contact with the cement, but there is no particular advantage in having more than the vertical sides of the insulating member thus prepared, and to sand the horizontal pori tion 5 would not materially increase the holding effect between the two parts, but in order to preserve the elastic or yielding property, the elastic material or coating 4 can be extended over those surfaces which have no substantial gripping or holding effect.

W'hen the connecting surface or surfaces of an insulating member 1 are thusprepared, or sanded, the insulating member is applied to a metal suspension cap 6 which is formed with a cup-shaped recess in which apart of the insulating member is inserted. and the recess is preferably formed with an undercut groove 7 atthe edge with internal holding ridges 8 at a distance from the edge and with a thin wall portion 9 at a greater distance from the edge. The insulating member fits somewhat loosely within the suspension cap 6, and the connect-ing cement 10 is applied between the sanded surface of the insulating member and the. adjacent coperating surface of the metal suspension cap 6, the cement engaging the projections of the particles 3 which extend above the yielding coating of the sanded surface previously described, or are thinly coated. p

In the same way a metal suspension pin 11 may be connected by means of cement 12 to an internal sanded surface 13 of the insulating member 1, as clearly shown in Fig. 1, the pin having holding grooves 14 for the cement, and making a yielding connection with the insulating member through the sanded surface thereof.

Between the inner end of the sus sion pin and the insulating member is a4 ad 15 of yield-ing materiahsuch as felt', paper, or the like. and between the edge of the metal suspension cap 6 and the adjacent surface of the insulating member `1 is a ring or pad 16, also of elastic material, such as felt, paper, or the like, to protect the surface of the insulating member, and to prevent it from being checked or-cracked due to the hardness or contact of the metal cap, and also for llO composed of a different material which has of parts, a vmetal suspension capyand properly spacing the edge of the cap and the fiange apart..

Instead of providin l this pad or gasket 16, the lower edge of t e metal cap may be provided with a thick coating 17 of yielding, material, as shown in Fig. 3, which will effectually space thev insulating member 1 and the cap apart; or the adjacent surface of the insulating' member itself may be painted or coated with elastic or yielding material 18, as shown in-Fig. 4, which serves the same purpose. In. either ca se the formation of a bead or rim 19 offset lon the outside ofthe edge of the cap does not form a rigid strut between the cap and the insulating member, as the yielding material 17 or 18, or the pad `16\islalso between the parts.

The advantage of insulators constructed in accordance with this linvention is that the projections formed are more or less resilient, which tends to relieve the main insulating members of stress which ma be set vup between them, the projections t us distributing 'the load or stress between the partsr since these projecting points tend to act as small elastic struts or s rings of reduced cross-section, thereby de ectingreadily un` der load and'relieving the main insulator parts of high stress at any particular point, the load being distributed by theI yielding of the projecting points. This, of course, is very valuable where the insulatorA is subjected to changing temperatures, and -by varying thesize and number of the project, ing points and the coating material, it is readily' seen that a wide rangein inelasticity may be provided for, and insulators thusv made are able to .withstand` the stresses due to expansion and contraction with less fref quent breakage.

This construction is particularly valuabley where an insulating member composed of porcelain, or the like, is to be attached to av suspension or connection member which is a different coeicientvof expansion and contraction, such as a metal of which thesus pension cap or pin`would be constru'cted, and it is very important that some yieldable connection be provided in an insulator which is made upl of metal and porcelain parts in order that the more frangible insulating material 'may not be broken due to the stress which would be` imposed upon it by the harder or stronger metal, if there were no yielding or elastic connections between them.

' `1. In an insulator composed of a plurality insulating member having coperating cenienting surfaces, the insulating-member having its cementing surface formedwith l uneven unglazed projections extending above a glazed surface and 'forming a substantially integral part of the member, a layer of yield parts united by a cement interposed between ,j

adjacent surfaces,'one of the partsA being a metal part and another of the parts being coinposed of an insulating material which has its cementing surface formed with a multiplicity of projections composed of ma' terial attached to the cementing surface by a vitreous glaze.

3. An insulator comprising a pluralityv of parts, one composed of metal, with corresponding surfaces for uniting the parts, some of the uniting surface of one of the parts being provided with projections, yielding material applied to the projections and to the uniting surface which has no projections,

and cement connectingthe said projections with thecorresponding surface of the metal part.

interposed between the `said-adjacent' edge i of the cap and the flange of the insulator.

5. An insulator comprising a pluralityofj' connected parts, one comprising a metal cap,

and another comprising-an insulating-mem-v ber having a boss insertible in the cap with an'extending fiange disposed adjacent thea-:1

edgerof the metal cap, parts having corresponding cementing surffaces and the cementing surface of the insu ating part being pro- ;vided with projections attached thereto, a

.coating of yielding material applied to the cementing surface and projections of the insulating part cement rigidly connecting said projections with `the corresponding surface.

iio`

of the other part to permit relative expansion and contraction of-the parts, and a pad of yielding material interposed between the adjacent edge-of the cap and the flange of the insulator.

6. A plurality of metal parts separated by an insulating member having corresponding surfaces for uniting the parts together,an

`insulating member having a portion of its corresponding surface provided with rojections extending abovev and integra ly at-r tached to the surface by a layer of glaze, a

layer ot' yielding material reposing on the unroughened surface of the insulator'member, and cement interposed between the corresponding surfaces of' the parts for holding the parts together.

7. An insulator comprising an insulating member and a metal cap therefor, said insulating memberhavinga portion of its surface adjacent said cap provided with a plurality of projections, cement interposed between said surface andfsaid cap, and'means for protecting the base/,portions of said projections from engagement ,with said cement.

v8. In an insulator composed of a plurality...

of parts, a metal suspension cap, and-an insulating member having cperating cementing surfaces, the insulating member having its connecting surface formed with uneven projections extending above a glazed surface and forming a substantial integral part of the member,'a layer off yielding material reposing on the projections and cement rigidly connecting the projections of the insulating member with the cementing surface of the suspension cap, so that a. yielding action between the parts may be had due to the contact of the cement with the said projections. n

Aug., A. D. 1918.

9. An insulator, comprising a plurality of parts united by a cement interposed between adjacent surfaces, y one of the parts being a metal part and another of the parts being composed of an insulating material which has its cementing surface formed with a together, the insulating member having a.

portion of its corresponding surface provided with projections extending above and integrally attached to the surface by a layer of glaze, a layer of yielding material interposed between the unroughened surface of the insulating member and the corresponding surface of the metal cap and cement interposed between the corresponding surfaces of'the -parts for holding the parts together.

n testimony whereof I have signed my name to this specification on this 8th day of Y ARTHUR O. AUSTIN. 

